lite: require jupyterlite[contents] for convenience

Author: datakurre

lite/jupyterlite-robotkernel/setup.cfg

@@ -44,7 +44,7 @@ install_requires =
     pkginfo
     jupyterlab-widgets
     jupyterlab-robotmode
-    jupyterlite ==0.1.0b4
+    jupyterlite[contents] ==0.1.0b4
 
 [options.packages.find]
 where =